States as international persons — In general — Recognition of acts of foreign States and governments — United States Act of State doctrine — Antitrust action — Defendant companies allegedly inducing dispute over territory between foreign States — Dispute adversely affecting plaintiff company to benefit of defendants — Whether action involving United States court in judging acts of foreign States — Status of the Trucial States — Whether States for purposes of Act of State doctrine — Whether action requiring United States court to adjudicate international boundary dispute — Whether foreign States indispensable parties to action — Scope of antitrust laws — Jurisdiction in antitrust cases — The law of the United States